ARTICLE IN PRESS

Teaching about Scientific Dissent from Neo-Darwinism

In their recent Opinion article in TREE [1], Eugenie Scott and Glenn Branch
argue that teaching students that there is a scientific controversy about the
validity of evolution is scientifically inappropriate and
pedagogically irresponsible. In so doing, Branch and Scott assume that
they have critiqued my position on the teaching of evolution. But they fail
to define their terms and engage the main arguments for my position, misrepresenting
it as a consequence. My position is not that students should be taught that
there is a scientific controversy over the validity of evolution per se, but
that they should be informed about the scientific controversies that exist about
neo-darwinism, the long-dominant theory of evolution.

I recently co-authored a major law review article [2] arguing for this pedagogical
proposal and have co-edited a peer-reviewed volume about the subject [3]. The
book develops a comprehensive pedagogical, legal and scientific case for exposing
students to the scientific controversies that exist about the key claims of
neo-darwinism, including the claim that the selectionmutation mechanism
can fully account for the appearance of design in biological systems. Scott
and Branch mention neither of these works, although my co-editor, the distinguished
Darwin-scholar John Angus Campbell, asked Scott to contribute a critical response
to the book, which she declined.

Instead of engaging the arguments of these works, Scott and Branch attempt
to associate our position with that of holocaust deniers and creation scientists.
They also repeatedly use the perjorative term anti-evolutionist,
thereby confusing the issue [4] and mischaracterizing the motives and rationale
of those of us who want to see students informed of the scientific controversies
that exist within and about aspects of contemporary darwinism.

Scott and Branch deny the existence of any significant scientific controversies
about the validity of evolution. But the credibility of their position
depends on definitional equivocation. All reputable scientists agree that evolution
happened, they insist. Overwhelming evidence reinforces this opinion.
And, of course, they are right if they equate evolution with change
over time or descent with modification (as they do when pressed).

Yes, life has changed over time. But, of course, neodarwinism affirms a good
deal more than that. In particular, it affirms that: (i) that an undirected
processes, principally natural selection acting on random mutations, is sufficient
to generate biological complexity; and (ii) all organisms have descended from
a common ancestor.

Scott herself acknowledges significant scientific debate about the sufficiency
of the neo-darwinian mechanism. Recently, in a public forum at the University
of San Francisco, she also acknowledged that many evolutionary biologists now
disagree about the truth of universal common descent. Our position, radical
though it might seem, is that students should be informed about such dissenting
opinion and, furthermore, that they should be told why some scientists doubt
aspects of neo-darwinism.

Thus, Scott and Branch misrepresent our position when they suggest that we
justify it mainly by an appeal to fairness. Teaching students about scientific
controversies is less a matter of fairness (still less, to religious sensibilities
as they imply) than it is a matter of full scientific disclosure. Students should
know, for example, that many embryologists dispute that different classes of
vertebrate embryos strongly resemble each other during their earliest stages
of development [5], althoughmanyAmerican biology textbooks claim or show the
opposite in their presentations of evolution (often using misleading photos
or Haeckels famously inaccurate drawings). Students should also know that
many scientists now question whether microevolutionary processes can be extrapolated
to account for macroevolutionary innovation and that the lack of such a mechanism
leaves unexplained the origin of major groups of animals, such as the Cambrian
Metazoa [6].

Scott and Branch acknowledge the existence of disputes about the sufficiency
of the neo-darwinism mechanism, but dismiss them as being of little consequence
to the status of contemporary evolutionary theory, as if the absence of an agreed
mechanism of macroevolutionary change constituted a minor theoretical lacuna.
Scott and Branch are forced by this logic, however, to defend a less than fully
neo-darwinian view of evolution.